Fluid cooling system, cooled fluid dispenser comprising the later, and methods for sterilization thereof

ABSTRACT

The present invention relates to a fluid cooling system ( 1 ), for use in dispensing or distributing a chilled or cooled fluid, comprising a primary heat exchanger system ( 2 ), a secondary heat exchanger system ( 3 ), a first conduit ( 9 ) through which fluid to be cooled or chilled is circulated, and a heat transfer agent ( 8 ) for transferring cooling energy to the fluid to be chilled circulating in the first conduit ( 9 ), wherein the primary and secondary heat exchanger systems ( 2, 3 ) are arranged at least partially one inside of another The invention also relates to cooled fluid dispensers incorporating the fluid cooling system and a methods for sterilization thereof.

FIELD OF THE INVENTION

The present invention relates to fluid cooling systems and cooled fluiddispensers. In particular, the present invention will be described andexplained in relation to cooled beverage dispensers, such as waterdispensers, commonly used for dispensing cooled or chilled drinkingwater or other chilled beverages.

BACKGROUND OF THE INVENTION

Fluid cooling systems adapted for use in cooled fluid dispensers aregenerally known from applicant's prior published applications EP 1 129024 and U.S. Pat. No. 6,442,960. In such systems, it is usual to find aprimary heat exchanger system and a secondary heat exchanger system,with a heat transfer agent being cooled in the primary exchanger system.A conduit for fluid flow is also present through which circulates afluid to be dispensed after cooling. Such cooling is effected bybringing the conduit containing the fluid to be dispensed into direct orindirect contact with the heat transfer agent that has previously beencooled by the primary heat exchanger system.

One of the problems of the known systems is that the primary andsecondary heat exchanger systems have to be quite voluminous in order toobtain the desired cooling effect of the liquid. This limits theirapplication to chilled fluid dispensers that are in turn voluminous, andcostly to run, cleanse or sterilize and maintain, and machine downtimeduring the cleansing or sterilization step is relatively high.

SUMMERY OF THE INVENTION

With a view to overcoming these problems, it is therefore one object ofthe present invention to provide a fluid cooling system, for example foruse in dispensing or distributing a chilled or cooled fluid, comprisinga primary heat exchanger system, a secondary heat exchanger system, afirst conduit through which fluid to be cooled or chilled is circulated,and a heat transfer agent for transferring cooling energy to the fluidto be chilled circulating in the first conduit, wherein the primary andsecondary heat exchanger systems are arranged at least partially oneinside of another.

Another object of the invention is a cooled or chilled fluid dispenser,incorporating a fluid cooling system as described above.

Still yet another object of the present invention is a sterilizationprocess for the fluid cooling system, and chilled fluid dispenser.

In accordance with the objects of the invention outlined above, theapplicant has found a way of reducing the volume of such fluid coolingsystems, while at the same maintaining the same or equivalent coolingefficiency, and increasing the ease with which the system and dispenserin which such systems are incorporated, can be maintained, viz. cleansedor sterilized. This opens up the applications of such fluid cooling anddispensing systems to other uses for which they were previouslyunsuitable or economically unviable, such as for dispensing cooled orchilled gaseous phase fluids, and for enabling such cooled fluids toflow through a sterilized circuit, e.g. in personal or domestic oxygendistribution appliances for respiratory assistance.

More particularly, the applicant, through the present invention havemanaged to reduce the volumes of heat transfer agent being circulated,and preferably also the volume of solid phase of heat transfer agentgenerated. This enables a reduction in the overall size of the fluidcooling system, and correspondingly any cooled or chilled fluiddispensing system into which it is incorporated. It is to be noted thatthe fluid cooling system of the present invention does not necessitatethe presence of primary heat source in the primary heat exchanger asdescribed in applicants prior application. Moreover, heat exchange isvastly improved with the arrangement as proposed in the presentinvention.

Consequently, one advantage of the present invention is that the fluidcooling system can be integrated into any chilled fluid dispensersystem, such as a drinking water dispenser. Furthermore, the fluidcooling system does not need to have a drainage pump, wheresterilization of the fluid cooling system or cooled fluid dispenser isnot required. This is optional in the event that sterilization of thecircuit including the first conduit is desired, for example, in adrinking water dispenser, or for distributing oxygen in a respiratoryassistance apparatus.

In a more preferred embodiment of the invention, the primary heatexchanger system is arranged at least partially, and more preferablysubstantially, within the secondary heat exchanger system. By the term“partially” or “substantially within”, it is meant that at least part,and preferably a major part, of the primary heat exchanger system isspatially located within the secondary heat exchanger system. Thisprovides for a very compact fluid cooling system according to theinvention and reduces the volumes of heat transfer agent that need to becirculated to obtain the desired cooling effect.

In one preferred embodiment of the present invention, the primary heatexchanger system comprises a chamber. The chamber is generally made of aplastic or metallic material, that will not deform or buckle under theoperating temperatures or pressures, in particular in relation to thecold temperatures generated, and can be generally cylindrical in shape,although other shapes could be envisaged easily by the skilled personthat would still be functional. The chamber is dimensioned to receive acoil, which coil serves to effect cooling thermal exchange with a heattransfer agent in the chamber of said primary heat exchanger system. Itwill be understood that other means of generating a cooling effect, forexample, using a finger and the Pelletier effect, or equivalent meanscan be used, instead of the coil. Advantageously, the primary heatexchanger system also comprises a thermostat, that enables regulation ofthe temperature of the heat transfer agent, thereby controlling thevolume of solid phase of the heat transfer agent that forms in thechamber. The terms “heat transfer agent” and “heat exchange agent” areused interchangeably in the present specification and claims and havethe meaning as defined hereafter. By “heat transfer agent” or “heatexchange agent”, it is meant an agent that can effectively transmit itsthermal energy to the fluid to be cooled and dispensed, preferablywithout the necessity for an important initial energy input. Preferredheat transfer agents are ones that undergo liquid/solid phasetransition. Water is the preferred heat transfer agent in this case,since the ice formed by the coil when water in the chamber comes intocontact with the coil tends to only thaw again slowly, thus releasingits cooling energy over time, and only requires minimal energy input atthe start. In addition, the use of water as heat transfer agent enablesice/water slurries to be circulated around the system for greater energytransfer efficiency should the need arise. Of course, other heattransfer agents that are commonly known could also be used, for example,halocarbons, such as fluorochlorocarbons, or hydrohalocarbons, solutes,solutions or dispersions that are involved in endothermic reactions bythe addition or extraction of water or another solvent, gaseous heattransfer agents, such as ammonia, or any heat transfer agents in whichendothermic reactions are involved and the like, that will all causeloss of heat energy from the liquid to be cooled. Other suitable heattransfer agents are monoethylene glycol, monopropylene glycol, and saltwater containing anti-corrosion agents.

In the preferred embodiment, the heat transfer agent circulates withinthe chamber of the primary heat exchanger system and between and aroundthe coil, which is set to withdraw heat from the heat transfer agent,and where the latter is water, cause the liquid to become partiallysolid and turn into ice. Such a system is typically known as an icebank. The volume of ice is controlled by the thermostat, that issuitably positioned within the chamber, for example inside the peripherydefined by the coil, or alternatively the thermostat can be placed inthe chamber at another location in the chamber, depending on the degreeof precision required in controlling the volume of solid phase formationof the heat transfer agent.

In the preferred embodiment of the present invention, the secondary heatexchanger system also comprises a chamber. This chamber substantiallysurrounds the chamber of the primary heat exchanger system, such thatthe latter system is substantially located within the chamber of thesecondary heat exchanger system. It will be understood that the chamberof the secondary heat exchanger system is generally adapted in shape andsize to receive the chamber from the primary heat exchanger system, andthus is most preferably generally cylindrical in shape, but of a greaterdiameter than that of the chamber of the primary heat exchanger system.

Preferably, the chamber of the primary heat exchanger system has anoutlet for the heat transfer agent which communicates with the chamberof the secondary heat exchanger system. The outlet of the chamber of theprimary heat exchanger system is even more preferably located in a wallof said chamber that is in contact with the chamber of the secondaryheat exchanger system. Most preferably, the outlet is located in an endwall of the cylindrically shaped chamber. In this way, the heat transferagent can circulate from the primary heat exchanger system to thesecondary heat exchanger system via the outlet in the end wall of thechamber of the primary heat exchanger system.

According to a particularly preferred embodiment of the presentinvention, the first conduit carrying the fluid to be cooled or chilledis located within the chamber of the secondary heat exchanger system.More preferably, the first conduit carrying the fluid to be cooled isarranged as a coil within the chamber and around a peripheral wallthereof, so that in effect, it is sandwiched between the outerperipheral wall of the chamber of the primary heat exchanger, and theinner peripheral wall of the chamber of the secondary heat exchanger,there being enough space between the two chambers and the first conduitfor heat transfer agent to circulate.

Preferably, the cooled heat transfer agent exiting via the outlet intothe chamber of the secondary heat exchanger system flows into saidchamber at one end of the chamber, over a peripheral surface of thefirst conduit, and out of said chamber via an outlet in a wall of saidchamber at another end of the chamber of the secondary heat exchangesystem. The volume of heat transfer agent in the chamber of the primaryheat exchanger system is such that upon phase change from liquid tosolid or from gas to solid, the remaining unsolidified but cooled volumeis displaced out of the chamber of the primary heat exchanger system andinto the chamber of the secondary heat exchanger system. The cooledliquid or gaseous heat transfer agent that is displaced then flows overthe first conduit as described, and as it comes into contact with thefirst conduit carrying the fluid to be cooled or chilled, warms up andis withdrawn via the outlet provided at the other end of the chamber inthe secondary heat exchanger system. In this way, the fluid beingcarried or circulated within the first conduit is cooled or chilled.

Advantageously, and preferably, the fluid cooling system also comprisesa reservoir for the heat transfer agent, located adjacent to the chamberof the secondary heat exchanger system. More preferably, the reservoiris located at a point higher than, or above, the chamber of thesecondary heat exchanger system. The reservoir for the heat transferagent can optionally be fitted with a plug comprising a membraneallowing any excess pressure created by the liquid/solid or gas/solidphase change to be vented out of the system. The reservoir can also beoptionally connected to a drainage pump enabling one or more chambers tobe drained of heat transfer agent for the purpose of sterilizing thefirst conduit. In this case, the reservoir is connected to the outlet ofthe chamber of the secondary heat exchanger system via the pump.

Additionally, and preferably, a second pump is provided to assist incirculating the heat transfer agent from one chamber to another, and ispreferably located at or near the heat transfer agent outlet of thechamber of the secondary heat exchanger system. This pump functionswhile fluid is being circulated in the chambers and can be stopped, ifdesired, before any drainage of the fluid cooling system occurs. Thefirst pump and second pump are preferably both connected to the outletprovided in the wall of the chamber of the secondary heat exchangersystem. Thus, in this way, the reservoir is also connected to thechamber of the secondary heat exchanger system via the first pump.

In an alernatively preterred embodiment, the primary heat exchangersystem is arranged at least partially, and more preferablysubstantially, around the secondary heat exchanger system. In thisembodiment, the primary heat exchanger system comprises a second conduitthat extends with and around the first conduit of the secondary heatexchanger, for at least part of the length of said first conduit. Thesecond conduit carries the heat exchange agent originating from theprimary heat exchanger. Preferably, the second conduit of the primaryheat exchanger is arranged around and along the length the first conduitof the secondary heat exchanger in such a way that sufficient coolingenergy is imparted by the heat exchange agent to cool the fluidcirculating within conduit. Most preferably, the second conduit of theprimary heat exchanger system extends coaxially along substantially thewhole of the length of the first conduit of the secondary heat exchangersystem. Alternatively, the second conduit of the primary heat exchangersystem is coiled around the periphery of the first conduit of thesecondary heat exchanger system. In yet another preferred alternative,the second conduit is arranged around the first conduit in one or moresections, such that heat transfer would occur from second conduit tofirst conduit at one or more non-contiguous regions or zones along thelength of the first conduit, in a manner sufficient to effect desiredcooling of the fluid within the first conduit. In the alternatelypreferred embodiment, the primary heat exchanger system comprises aseparate coil and chamber for transferring cooling energy to the heattransfer agent, distant from the second conduit. In other words, theprimary heat exchanger system has a distinct energy transfer unit forcooling the heat transfer agent that is located at a distance from thesecond conduit of the secondary heat exchanger system. In such a case,the primary heat exchanger also comprises a thermostat for regulatingthe temperature of the the heat transfer agent, and hence the liquid tobe cooled. As defined in the present specification and claims, the termthermostat is understood to mean electronic or electromechanicaltemperature sensors or detectors, or bimetallic strips for example. Morepreferably, the primary heat exchanger system also comprises a pumpconnected to the chamber of the primary heat exchanger system. The pumpfacilitates circulation of the heat transfer agent to the secondary heatexchanger system. The chamber of the primary heat exchanger system canbe connected to the second conduit of the primary heat exchanger systemvia an outlet leading from said chamber to said second conduit. Theintroduction of heat transfer agent into the second conduit canoptionally also be run counter-current to the flow of the liquid to becooled circulating in the first conduit.

As has been stated previously, it may be desired to be able to sterilizethe fluid cooling system. For such a case, it is optionally preferredthat the primary heat exchanger system also comprise a heat transferagent recovery tank or reservoir for the heat transfer agent.Preferably, the heat transfer agent recovery tank is connected to thepump. Even more preferably, the second conduit is also connected to theheat transfer agent recovery tank, thereby forming a circuit.Optionally, the fluid cooling system can also comprise a switchconnected to said second conduit to effect recovery of the heat transferagent into the recovery tank.

As mentioned previously, the invention proposes a fluid cooling system.In the present specification and claims, the term “fluid” is intended tocover both liquids and gases. In a particularly preferred embodiment,the fluid to be cooled and dispensed is a liquid and comprisesnon-alcoholic beverages, such as fruit juice, water, drinking water, andalcoholic beverages, such as beer, wine, and spirit liquors. In analternatively preferred embodiment, the fluid to be cooled and dispensedis a gas, and comprises air, oxygen, nitrogen, helium, hydrogen, nitrousoxide. Other fluids can also be envisaged, for example, biologicalfluids, such as blood, plasma, saline solutions, nutritive solutions,fluid pharmaceutical preparations and the like.

Optionally, but advantageously, it can be desirable to enable the fluidcooling system to be cleansed and sterilized. Accordingly, one preferredembodiment of the fluid cooling system is that the first conduit issterilized periodically.

Another object of the invention, as mentioned briefly previously, is acooled fluid dispenser comprising a source of fluid to be cooled anddispensed, and at least one dispenser tap, wherein the dispenserincorporates a fluid cooling system as previously defined. Inparticular, the cooled fluid dispenser according preferably furthercomprises another dispensing tap connected to the source of fluidindependently from said fluid cooling system. Such second dispensing taptypically will dispense fluid that has not been cooled, that is to say,will be connected directly to the source of the fluid. This can beuseful for example in beverage dispensers such as water dispensers whereone can offer the choice of chilled or cooled drinking water through onedispensing tap and water at room temperature, or heated, through anotherdispensing tap. Preferably, the source of fluid to be cooled anddispensed is removable, and more preferably is selected from the groupconsisting of a pressurized or non-pressurized bottle, canister, andtank.

Yet another object of the present invention is a method for thesterilization of a fluid cooling system or a cooled fluid dispenser,comprising the following steps:

-   -   draining a chamber carrying a heat transfer agent in a primary        heat exchanger system;    -   optionally draining a first conduit carrying fluid to be cooled        and dispensed;    -   sterilizing the first conduit for a length of time sufficient to        cause bacteriological destruction and sterilization.

Still yet another object of the present invention is a method for thesterilization of a fluid cooling system or a cooled fluid dispenser,comprising the following steps:

-   -   draining a second conduit carrying a heat transfer agent in a        primary heat exchanger system;    -   optionally draining a first conduit carrying fluid to be cooled        and dispensed;    -   sterilizing the first conduit for a length of time sufficient to        cause bacteriological destruction and sterilization.

Preferably, the sterilization step in such methods comprises flushingthe first conduit with a sterilizing agent, more preferably with asolution of sulfamic acid.

In a most preferred embodiment, however, the sterilization stepcomprises heating the first conduit to a temperature that is maintainedfor a time sufficient to cause bacteriological destruction andsterilization. This can be achieved by application of an electriccurrent to substantially each end of said first conduit. In thispreferred sterilization step, the heating causes any remaining fluid inthe first conduit to reach sterilization temperature and travel alongsaid conduit, thereby effecting sterilization of said conduit.Advantageously, the dispensing taps in cooled fluid dispenser are alsosterilized. In another optional, yet advantageous step, a fluid sourceperforator connectable to a fluid source to be cooled and dispensed isalso sterilized. Typically, cooled fluid dispensers such as drinkingwater dispensers have a removable bottle or tank as fluid source with aseal that is punctured or perforated by the perforator upon placing thefluid source on the dispenser. The perforator is generally connected toat least the first conduit, and optionally also to a second dispensingtap, and comprises a valve enabling passage of air into the tank orbottle of the fluid source, thereby ensuring that the fluid can escapefrom the tank or bottle into the fluid cooling system or the seconddispensing tap.

The invention will now be explained in more detail with reference to theenclosed figures, which merely illustrate two preferred examples of thefluid cooling system of the present invention.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 represents a schematic section view of a preferred embodiment ofthe fluid cooling system of the present invention, including means foroperating sterilization of the system;

FIG. 2 represents a schematic section view of the same fluid coolingsystem shown in FIG. 1, except that the means for sterilization are nolonger present;

FIG. 3 represents a perspective view from the right of an alternativepreferred embodiment of the fluid cooling system of the presentinvention;

FIG. 4 represents a perspective view from the left of the samealternative embodiment of the fluid cooling system shown in FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION Example 1

The fluid cooling system, indicated generally by reference 1, is amachine based on an ice bank system. The system 1 comprises a primaryheat exchanger system, identified generally by the reference 2, and asecondary heat exchanger system, identified generally by the reference3. The primary and secondary heat exchangers systems 2,3 each comprise achamber 4,5 respectively. The chambers 4,5 are made of a plasticmaterial. Chamber 4 of the primary heat exchanger system 2 houses anevaporator or coil 6 which is connected to a standard refrigerationsystem (not shown) outside of the primary 2 and secondary 3 heatexchanger systems. As can be seen from the FIGS. 1 and 2 chamber 4 ispartly housed within chamber 5. The chambers 4 and 5 are preferablygenerally cylindrical in shape. The primary heat exchanger system 2 alsocomprises a thermostat 7, as defined previously, designed to regulatethe temperature of heat transfer agent 8, in this case water containedinside chamber 4. In chamber 4 ice as the heat transfer agent 8 in thesolid phase is made by the evaporator or coil 6. The volume of ice 8 iscontrolled by a thermostat 7 located in the chamber close to theevaporator or coil 6.

In the secondary heat exchanger system 3, the chamber 5 houses a firstconduit 9 in the shape of a stainless steel coil, which takes the fluidto be cooled 10, in this case drinking water, from a bottle (not shown)to a dispensing tap (not shown). Alternatively, the fluid to be cooledcan be obtained by direct connection of the system to a distributednetwork of fluid, such as a tap water network. Any increase in thetemperature of the drinking water 10 inside the first conduit 9 isdetected by a second thermostat 11 located in the second chamber 5 nextto the conduit 9. Pump 12 is activated by this second thermostat 11 andthe warm heat transfer agent 8, in this case water, is drawn from thesecond chamber 5 via outlet 24 and pumped into the first chamber 4. Thiswarm heat transfer agent 8 is replaced by cold heat transfer agent 8from the first chamber 4 via outlet 16. The heat transfer agent 8 isdeflected by a deflector plate 13 on its entry into the first chamber 4in order to ensure that the heat transfer agent 8 coming from the secondchamber 5, comes into contact with the solid phase heat transfer agent,i.e. the ice bank 8, to maintain the temperature of the heat transferagent 8 at a sufficiently low level in the second chamber 5. Thetemperature of the fluid to be cooled 10, in this case water, inside thefirst conduit 9 is thereby reduced to the required level. As can be seenfrom FIGS. 1 and 2, a majority of the first conduit 9 is immersed in thecooling heat transfer agent 8 in the second chamber 5 of the secondaryheat exchanger system 3.

One of the most efficient methods of sanitizing the fluid cooling systemis to heat all the tubing used to carry the drinking water. This processis also environmentally friendly because it doesn't use any chemicalproducts.

In the method according to the present invention, an electrical currentis used to heat all the stainless steel tubing carrying the fluid to becooled. The method involves using an electrical resistance (not shown)which is connected to an electric transformer (not shown). A highcurrent, for example 80 A under a low voltage, for example 7.1 V travelsinto the secondary circuit of the transformer and a resistance. Theresistance is heated by the current passing through. It will beunderstood that the skilled person will adapt the current and amperageto correspond to the materials used in the cooling fluid circuit and thesurface area available. The temperature is determined by the length oftime the current is passed through the resistance. The longer the time,the higher the temperature. In the present method, the electricalresistance is composed of the resistances of the stainless steel tubeconstituting the first conduit 9, optionally a perforator 14 and a partof the air circuit comprising an air filter 15, i.e. the drinking watersystem. Optionally, the taps mays also form part of the circuit. Allthese parts are linked by welding or brazing to ensure a good andcontinuous electrical conductivity. The dimensions of these parts areadapted to obtain the necessary electrical resistance. The fluid coolingsystem is connected to the electrical transformer, located outside theprimary 2 and secondary 3 heat exchangers, with copper wires or othersuitable material connecting two plates brazed onto the fluid coolingsystem. The first connection is made to the tube 15 which allows air topass into 10 the system and the second on the first conduit 9 justbefore the tap. Bridging connections are also provided at differentpoints in the circuit to close the electrical circuit and maximize theheating effect. The power of the transformer is for example about 400 W,but will be adjusted accordingly as a function of the materials used,generally between 200 W and 500 W.

In order to carry out sterilization using this apparatus, the fluidcooling system 1 is also equipped with a second pump 17, a heat transferagent recovery or storage tank 18, a tube 19 connecting the second pump17 to the storage tank 18, and an outlet 21 for communication of thepump with chamber 5 via outlet 24. The storage tank also comprises aplug 20 comprising a filter vent for relieving any excess pressure inthe system caused by the build up of solid phase heat transfer agent 8in chamber 4. Before sterilization can begin, pump 12 is optionallystopped, and pump 17 activated to pump out the heat transfer agent 8from chamber 5 via outlets 24 and 21 through tube 19 to storage tank 18.Once the heat transfer agent 8 has been removed from chamber 4, thefluid source is removed, and any fluid to be cooled remaining in thefirst conduit 9 is evacuated either from the system via pipe 23 whichleads to a dispensing tap (not shown), if an air pump is present, orelse just by heating the circuit. If an air pump is present, the aim ofwhich is decrease the time spent for sterilization, the electric currentas described above can be applied, leading to heating of the firstconduit 9, which in turn leads to heating of any fluid drops remainingin the first conduit 9 causing vapor to be formed or superhot gas. Thetemperature of this gas or vapor, is sufficient to sterilize the circuitand destroy any bacteriological infection. After sterilization, a newfluid source is placed onto the fluid cooling system, and the secondpump 17 stopped, and the heat transfer agent 8 flows down via gravityfrom the storage tank 18 via tube 19 and via the pump and outlets 21 and24 into chamber 5. Once the heat transfer agent 8 has been returned backinto chamber 5, the pump 12 can be restarted, it was previously stopped,and operation of the cooling system can recommence. The advantage ofhaving the second pump 17, storage tank 18 and connecting tube 19 andoutlets 24 and 21 is that operational downtime is reduced since drainageand refilling of the chamber 5 is accelerated.

The only differences of the embodiment represented in FIG. 2 with thatof FIG. 1 are that the FIG. 2 embodiment does not comprise a second pump17, storage tank 18, or connecting tube 19. The fluid cooling systemdoes however have outlets 24 and 21, closed by a plug 25, that enablemanual drainage and refilling of chamber 5, which will have to berefilled manually after any sterilization operation takes place.

Example 2

The fluid cooling system, shown in FIGS. 3 and 4, and indicatedgenerally by reference 101 comprises a primary heat exchanger, indicatedgenerally by reference 102, a secondary heat exchanger indicatedgenerally by reference 103, and a tank 118 that functions as a reservoiror storage tank to prime the pump 112 via tube 127 with heat exchangeagent 108 and as a recovery unit for this same heat exchange agent 108.

The primary heat exchanger 102, in which cooling of the heat exchangeagent occurs, comprises a tank or chamber 104, containing the heatexchange agent 108 that can be in either the fluid or solid phase arounda coil (not shown), or a finger or other equivalent means known to theskilled person, but substantially as described for the preferredembodiment illustrated in FIGS. 1 and 2. The coil, in this case, is madeof a suitable material that enables efficient energy transfer from thecoil to the primary heat exchange agent, and is preferably made ofmetal, for example copper, such that the heat exchange agent 108 canpass from the fluid to the solid phase and vice-versa. The volume of thesolid phase of the heat exchange agent 108 in the primary heat exchangechamber 104 is controlled by a thermostat or equivalent means well knownto the skilled person, and as described for FIGS. 1 and 2. Thethermostat is therefore responsible for starting and stopping thecooling operation.

The secondary heat exchanger 103 comprises a first conduit 109 withinwhich a fluid to be dispensed circulates, for example, a beverage suchas drinking water. A second conduit 126, of greater diameter than thefirst conduit 109, extends with and around the first conduit 109, for atleast part of the length of the first conduit 109. The second conduit126 carries the heat exchange agent 108 originating from the primaryheat exchanger 102. The second conduit 126 is arranged around theconduit along its length in such a way that sufficient cooling energy isimparted by the heat exchange agent 108 to cool the fluid circulatingwithin conduit 109. The second conduit 126 extends coaxially alongsubstantially the whole of the length of the first conduit 109. As canbe seen from FIGS. 3 and 4, the two conduits 109,126 form a generallyspiral, coiled configuration 131.

The two heat exchangers 102, 103 are connected in circuit by a tank 118,that functions as a buffer tank and primer for pump, with a pump 112that circulates the heat exchange agent 108 from the primary heatexchanger system 102 to the secondary heat exchanger system 103.

The temperature of the secondary heat exchanger 103 system is controlledindirectly by a thermostat present in the first heat exchanger system102 or equivalent means that controls the activation of the pump 112.Preferably, the thermostat is set to activate the pump 112 as soon asfluid is withdrawn from any of the dispensing taps 128, 129. Thethermostatic control of the secondary heat exchanger 103 is also used tomaintain a predetermined temperature of the fluid to be dispensed.

The heat exchange agent 108 or heat transfer agent can also be retainedin the tank 118 for optional cleansing of the apparatus. Duringcleansing, or sterilization of the first conduit 109 carrying the fluidto be dispensed, draining of the heat exchange agent 108 can be operatedby opening a switch activated electromechanical valve 130 or the like.The electromechanical valve 130 sets the highest point of the firstconduit 109 at the same pressure as the tank 118 and the heat exchangeagent 108 then drops into the tank 118 via tube 131 and aftersterilization can be transferred with the pump to the primary heatexchanger 102 via tubes 132 and 133. At this moment in time, the pump112 is stopped.

Sterilization can be accomplished in several ways. One such way is byoptionally removing the source of fluid to be cooled and dispensed,opening the dispensing taps 128, 129 and flushing the first conduit withsterilizing solution, such as a solution of sulphamic acid. This alsoresults in removal of scale. In a particularly preferred embodimenthowever, the second conduit 126 is drained into the tank 118 asdescribed previously, and then the first conduit 109 can also optionallybe drained, for example by opening the dispensing taps 128, 129, leavingonly trace amounts of fluid to be dispensed. The first conduit 109 canthen be sterilized by application of an electrical current, as wasdescribed for the embodiment illustrated in FIG. 1 and example 1. Thiselectrical current, which heats up the material from which the conduitis made, causes trace amounts of fluid, or any fluid, still left in thefirst conduit to heat up, and through alternate blocking and opening ofthe fluid inlet, for example with a cap, and the dispensing taps 128,129 at the appropriate moment, it is possible to cause the hot vaporformed to travel down the circuit from the inlet to the dispensing taps128, 129, thereby sterilizing the conduit 109. Complete sterilization ofthe conduit 109 can be obtained by causing electrical current to passfor sufficient time to heat up the trace amounts of fluid to atemperature sufficient to destroy enough bacteria present in the conduit109 to a level that satisfies any necessary hygiene requirements.Generally, complete sterilization can be obtained by heating with asystem as previously described after about 2 to about 10 minutes, andoptionally longer. After sterilization has completed, the heat exchangeagent 108 can be reintroduced into the primary and secondary heatexchangers 102, 103 by closing the electromechanical valve 130 andswitching the pump 118 back on.

An alternative embodiment to this way of operating can be obtained bynot providing a tank, and only incompletely filling the primary heatexchanger 102 with heat exchange agent 108. When it is desired tosterilize the conduit 109, heat exchange agent 108 is removed from thesecondary heat exchanger 103 system by stopping the pump, so that heatexchange agent 108 is drawn back by gravity into the primary heatexchanger 102. In this way, when the pump 112 is stopped by thethermostat, the remaining heat exchange agent 108 in the second conduit127 automatically drops out under the effect of gravity, thereafterpermitting sterilization of the conduit 109 as described above. At thismoment, it is possible to use the first conduit 109 to carry anddistribute fluid at room temperature if so desired.

1. A fluid cooling system, for use in dispensing or distributing achilled or cooled fluid, comprising a primary heat exchanger system, asecondary heat exchanger system, a first conduit through which fluid tobe cooled or chilled is circulated, and a heat transfer agent fortransferring cooling energy to the fluid to be chilled circulating inthe first conduit, wherein the primary and secondary heat exchangersystems are arranged at least partially one inside of another, andwherein the primary heat exchanger system comprises a chamber locatedsubstantially within a chamber of the secondary heat exchanger system,and wherein the chamber of the primary heat exchanger system has anoutlet for the heat transfer agent which communicates with the chamberof the secondary heat exchanger system, and wherein the outlet of thechamber of the primary heat exchanger system is located in a wall ofsaid chamber that is in contact with the chamber of the secondary heatexchanger system.
 2. A fluid cooling system according to claim 1,wherein the primary and secondary heat exchanger system chambers arearranged substantially one inside of another.
 3. A fluid cooling systemaccording to claim 1, wherein the primary heat exchanger system chamberis arranged at least partially within the secondary heat exchangersystem chamber.
 4. A fluid cooling system according to claim 1, whereinthe primary heat exchanger system chamber is arranged substantiallywithin the secondary heat exchanger system chamber.
 5. A fluid coolingsystem according to claim 1, wherein the primary heat exchanger systemalso comprises a coil that effects cooling thermal exchange with theheat transfer agent in the chamber of said primary heat exchangersystem.
 6. A fluid cooling system according to claim 1, wherein theprimary heat exchanger system also comprises a thermostat.
 7. A fluidcooling system according to claim 1, wherein the first conduit carryingthe fluid to be cooled is located within the chamber of the secondaryheat exchanger system.
 8. A fluid cooling system according to claim 1,wherein the first conduit carrying the fluid to be cooled is arranged asa coil around a peripheral wall of the chamber of the primary heatexchanger system.
 9. A fluid cooling system according to claim 1,wherein the fluid cooling system also comprises a reservoir for the heattransfer agent, located adjacent to the chamber of the secondary heatexchanger system.
 10. A fluid cooling system according to claim 9,wherein the reservoir is located above the chamber of the secondary heatexchanger system.
 11. A fluid cooling system according to claim 9,wherein the reservoir is connected to the outlet of the chamber of thesecondary heat exchanger system via a pump.
 12. A fluid cooling systemaccording to claim 1, wherein the secondary heat exchanger system alsocomprises a pump for circulating heat transfer agent.
 13. A fluidcooling system according to claim 1, wherein the primary heat exchangersystem is arranged at least partially around the secondary heatexchanger system.
 14. A fluid cooling system according to claim 1,wherein the primary heat exchanger system is arranged substantiallyaround the secondary heat exchanger system.
 15. A fluid cooling systemaccording to claim 1, wherein the fluid to be cooled is a liquid.
 16. Afluid cooling system according to claim 1, wherein the fluid is a liquidand comprises non-alcoholic beverages, such as fruit juice, water,drinking water, and alcoholic beverages, such as beer, wine, and spiritliquors.
 17. A fluid cooling system according to claim 1, wherein thefluid to be cooled is a gas.
 18. A fluid cooling system according toclaim 1, wherein the fluid is a gas and comprises air, oxygen, nitrogen,helium, hydrogen, nitrous oxide.
 19. A fluid cooling system according toclaim 1, wherein the first conduit is sterilized periodically.
 20. Acooled fluid dispenser comprising a source of fluid to be cooled anddispensed, and at least one dispenser tap, wherein the dispenserincorporates a fluid cooling system according to claim
 1. 21. A cooledfluid dispenser according to claim 20, wherein the dispenser furthercomprises another dispensing tap connected to the source of fluidindependently from said fluid cooling system.
 22. A cooled fluiddispenser according to claim 20, wherein the source of fluid to becooled and dispensed is removable.
 23. A cooled fluid dispenseraccording to claim 20, wherein the removable source of fluid is selectedfrom the group consisting of a pressurized or non-pressurized bottle,canister, and tank.
 24. A fluid cooling system, for use in dispensing ordistributing a chilled or cooled fluid, comprising a primary heatexchanger system, a secondary heat exchanger system, a first conduitthrough which fluid to be cooled or chilled circulated, and a heattransfer agent for transferring cooling energy to the fluid to bechilled circulating in the first conduit, wherein the primary andsecondary heat exchanger systems are arranged at least partially oneinside of another, and wherein the primary heat exchanger systemcomprises a chamber located substantially within a chamber of thesecondary heat exchanger system, and wherein the chamber of the primaryheat exchanger system has an outlet for the heat transfer agent whichcommunicates with the chamber of the secondary heat exchanger system,and wherein the heat transfer agent circulates from the primary heatexchanger system to the secondary heat exchanger system via the outletin a wall of the chamber of the primary heat exchanger system.
 25. Afluid cooling system according to claim 24, wherein the primary andsecondary heat exchanger system chambers are arranged substantially oneinside of another.
 26. A fluid cooling system according to claim 24,wherein the primary heat exchanger system chamber is arranged at leastpartially within the secondary heat exchanger system chamber.
 27. Afluid cooling system according to claim 24, wherein the primary heatexchanger system chamber is arranged substantially within the secondaryheat exchanger system chamber.
 28. A fluid cooling system according toclaim 24, wherein the primary heat exchanger system also comprises acoil that effects cooling thermal exchange with the heat transfer agentin the chamber of said primary heat exchanger system.
 29. A fluidcooling system according to claim 24, wherein the primary heat exchangersystem also comprises a thermostat.
 30. A fluid cooling system accordingto claim 24, wherein the first conduit carrying the fluid to be cooledis located within the chamber of the secondary heat exchanger system.31. A fluid cooling system according to claim 24, wherein the firstconduit carrying the fluid to be cooled is arranged as a coil around aperipheral wall of the chamber of the primary heat exchanger system. 32.A fluid cooling system according to claim 24, wherein the fluid coolingsystem also comprises a reservoir for the heat transfer agent, locatedadjacent to the chamber of the secondary heat exchanger system.
 33. Afluid cooling system according to claim 32, wherein the reservoir islocated above the chamber of the secondary heat exchanger system.
 34. Afluid cooling system according to claim 32, wherein the reservoir isconnected to the outlet of the chamber of the secondary heat exchangersystem via a pump.
 35. A fluid cooling system according to claim 24,wherein the secondary heat exchanger system also comprises a pump forcirculating heat transfer agent.
 36. A fluid cooling system according toclaim 24, wherein the primary heat exchanger system is arranged at leastpartially around the secondary heat exchanger system.
 37. A fluidcooling system according to claim 24, wherein the primary heat exchangersystem is arranged substantially around the secondary heat exchangersystem.
 38. A fluid cooling system according to claim 24, wherein thefluid is a liquid and comprises non-alcoholic beverages, such as fruitjuice, water, drinking water, and alcoholic beverages, such as beer,wine, and spirit liquors.
 39. A fluid cooling system according to claim24, wherein the fluid to be cooled is a gas.
 40. A fluid cooling systemaccording to claim 24, wherein the fluid is a gas and comprises air,oxygen, nitrogen, helium, hydrogen, nitrous oxide.
 41. A fluid coolingsystem according to claim 24, wherein the first conduit is sterilizedperiodically.
 42. A cooled fluid dispenser comprising a source of fluidto be cooled and dispensed, and at least one dispenser tap, wherein thedispenser incorporates a fluid cooling system according to claim
 24. 43.A cooled fluid dispenser according to claim 42, wherein the dispenserfurther comprises another dispensing tap connected to the source offluid independently from said fluid cooling system.
 44. A cooled fluiddispenser according to claim 42, wherein the source of fluid to becooled and dispensed is removable.
 45. A cooled fluid dispenseraccording to claim 42, wherein the removable source of fluid is selectedfrom the group consisting of a pressurized or non-pressurized bottle,canister, and tank.
 46. A fluid cooling system, for use in dispensing ordistributing a chilled or cooled fluid, comprising a primary heatexchanger system, a secondary heat exchanger system, a first conduitthrough which fluid to be cooled or chilled is circulated, and a heattransfer agent for transferring cooling energy to the fluid to bechilled circulating in the first conduit, wherein the primary andsecondary heat exchanger systems are arranged at least partially oneinside of another, and wherein the primary heat exchanger systemcomprises a chamber located substantially within a chamber of thesecondary heat exchanger system, and wherein the chamber of the primaryheat exchanger system has an outlet for the heat transfer agent whichcommunicates with the chamber of the secondary heat exchanger system,and wherein cooled heat transfer agent exiting via the outlet into thechamber of the secondary heat exchanger system flows into said chamberat one end of said chamber, over a peripheral surface of the firstconduit, and out via an outlet in a wall of the chamber at another endof the chamber of the secondary heat exchange system.
 47. A fluidcooling system, for use in dispensing or distributing a chilled orcooled fluid, comprising a primary heat exchanger system, a secondaryheat exchanger system, a first conduit through which fluid to be cooledor chilled is circulated, and a heat transfer agent for transferringcooling energy to the fluid to be chilled circulating in the firstconduit, wherein the primary and secondary heat exchanger systems arearranged at least partially one inside of another, and wherein thesecondary heat exchanger system comprises a chamber, and wherein thefluid cooling system also comprises a reservoir for the heat transferagent, located adjacent to the chamber of the secondary heat exchangersystem, and wherein the reservoir comprises a plug comprising an excesspressure-venting membrane.
 48. A fluid cooling system according to claim47, wherein the chamber of the primary heat exchanger system has anoutlet for the heat transfer agent which communicates with the chamberof the secondary heat exchanger system.
 49. A fluid cooling systemaccording to claim 47, wherein the primary and secondary heat exchangersystem chambers are arranged substantially one inside of another.
 50. Afluid cooling system according to claim 47, wherein the primary heatexchanger system chamber is arranged at least partially within thesecondary heat exchanger system chamber.
 51. A fluid cooling systemaccording to claim 47, wherein the primary heat exchanger system chamberis arranged substantially within the secondary heat exchanger systemchamber.
 52. A fluid cooling system according to claim 47, wherein theprimary heat exchanger system also comprises a coil that effects coolingthermal exchange with the heat transfer agent in the chamber of saidprimary heat exchanger system.
 53. A fluid cooling system according toclaim 47, wherein the primary heat exchanger system also comprises athermostat.
 54. A fluid cooling system according to claim 47, whereinthe first conduit carrying the fluid to be cooled is located within thechamber of the secondary heat exchanger system.